President Trump likely will fulfill a campaign promise this month by curbing some of the ties with Cuba that former president Barack Obama adopted when he made his historic overture to the communist island.

Trump threatened during campaign stops in the Cuban-American enclave of Miami to cut ties with Cuba. After winning the election, he tweeted that he might "terminate" Obama's renewal of diplomatic relations with Cuba, which ended more than 50 years of estrangement that began during the Cold War.

Cuban experts say Trump has backed off that stance, noting he has been preoccupied with other issues, plus a broad collection of American businesses have benefited from the opening.

"All the initial signs were that he was going to reverse everything," said Frank Mora, a former Defense Department official under Obama and now director of the Kimberly Green Latin American and Caribbean Center at Florida International University in Miami. "But (Trump) doesn't really care about Cuba. There's going to be much more symbolism in the kinds of changes they will announce than anything substantive."

A report released Thursday by Engage Cuba, a Washington-based group, estimated that American companies would lose $6.6 billion and more than 12,000 U.S. jobs over Trump's first term if he reversed course.

Opponents of Obama's policy say it has done nothing to change Cuba's communist system and repression. The Havana-based Cuban Commission for Human Rights and National Reconciliation said the government has detained more than 400 political prisoners each month this year, a drop from 2016 but a constant reminder of Cubans' limited rights.

Trump is expected to announce the changes some time in June, possibly during a visit to Miami. Here are some key aspects of Obama's opening with Cuba that could be at risk:

EMBASSIES

Even hard-line opponents of renewed ties don't expect Trump to shut down diplomatic relations and close the recently reopened embassies in Washington and Havana.

The opening has allowed greater dialogue between the two governments, which have held dozens of high-level meetings that led to limited postal service, more intelligence sharing and government cooperation on drug interdiction, emergency response and environmental challenges.

Frank Calzon, executive director of the Center for a Free Cuba and one of the loudest critics of Obama's opening, acknowledged he doesn't want to see the embassies shuttered again. "You can never go back," he said.

One of the most tangible changes under Obama was re-establishing direct commercial flights between the Cold War foes. Now, Americans traveling to Cuba under one of 12 categories approved by the U.S. government can hop online and book a flight.

The demand has not been as high as expected, prompting several airlines to scale back their flights and three — Spirit Airlines, Frontier and Silver Airways — to cancel all their Cuba flights. Pedro Freyre, an attorney with the Akerman law firm who brokered multiple deals between U.S. companies and Cuba, said Trump is unlikely to further punish U.S.-based airlines by canceling their limited runs.

"The invisible hand of the market is already working its magic," Freyre said.

Cruise operators continue pushing ahead. Norwegian Cruise Line, Carnival Corp. and Royal Caribbean Cruises have announced more than 200 sailings to the island in the next three years, according to the New York-based U.S.-Cuba Trade and Economic Council. Few expect those to be limited, since passengers mostly spend their nights on the American cruise ships and aren't handing money to Cuban-owned hotels.

HOTELS

One likely area for change is the ability of U.S.-owned companies to manage hotel properties in Cuba.

Starwood Hotels & Resorts signed a deal with the Cuban government to operate — but not own — three landmark hotels in Havana. That arrangement angered Sen. Marco Rubio, R-Fla., Rep. Mario Diaz-Balart, R-Fla., and other Cuban-Americans because the deal made Starwood partners with the Cuban military, the largest hotel operator on the island.

"If the Americans want to deal with hotels in Cuba, the administration ought to find a way in which those hotels function as foreign hotels, as they do in other countries," Calzon said. "The idea is not to finance the Cuban military."

Airbnb could survive. The San Francisco-based company was one of the first to take advantage of the diplomatic opening with Cuba and now helps more than 8,000 Cubans rent their homes to tourists. Those visits mostly benefit Cuban homeowners, meaning Trump could allow that relationship to continue.

A woman posses while smoking a cigar at the Habano Festival opening in Havana on Feb. 29, 2016.(Photo: Ernesto Mastrascusa, EPA)

CIGARS AND RUM

One of the most popular changes under Obama was the free flow of Cuba's legendary rum and cigars.

His administration allowed Americans to return from Cuba with up to $100 worth of the items. That was later expanded so people traveling anywhere in the world can come back to the U.S. with as many bottles and boxes they wanted, as long as the items were for personal use.

Those changes are in jeopardy because the island's rum and cigar companies are state owned, meaning most profits go to the Cuban government. Even supporters of more trade and travel with Cuba believe allowing rum and cigars will be shut down.

"That one is likely to be reversed," Freyre said. "If I were to be in favor of any changes, which I'm not, I would be in favor of that one. It's just so frivolous."

VISAS

Because of the economic embargo the U.S. maintains on Cuba, tourism remains off limits. Securing a visa was one of the hardest aspects of traveling to Cuba before Obama renewed diplomatic ties, because Americans had to get approval through the U.S. Office of Foreign Assets Control, which was often handled by travel agencies. Travelers also had to show their visit complied with one of 12 allowable reasons, such as religious, educational or humanitarian trips.

The Obama administration made that process far simpler, allowing travelers to purchase their visas at airline counters and simply attest that they were going to Cuba for legal reasons. Calzon believes too many people take advantage of that process and visit Cuba simply as tourists.

Trump could make it more difficult to travel to Cuba, leading to fewer Americans willing to take the risk.

People line up in Havana at an office of a financial service and money transfer agent on Jan. 15, 2015. Cuban-Americans in the U.S. are allowed to send more money back torelatives in Cuba under changes made by former president Barack Obama.(Photo: Yamil Lage, AFP/Getty Images)

HELP TO CUBANS

Obama allowed Cuban-Americans to send unlimited amounts of money to relatives on the island. Trump could reimpose limits on those money transfers because the Cuban government takes a cut of each money transfer as a steady stream of income.

It's unclear whether Trump will limit those remittances, but Freyre said that decision should not be political, but a humanitarian one.

"Even staunch defenders of the embargo say, 'Don't mess with the families,'" Freyre said. "If you now come out and say you can no longer send money to your grandmother, that's just mean-spirited."